Go to Services.msc and restart WSUS Service. Also make sure to delete MMC Console cache located at %appdata%\Microsoft\MMC

After that I was able to open the console. But the KB article requires below changes too.

CMD go to “C:\Program Files\Update Services\WebServices\ClientWebService\” path and execute below command to take the ownership of the file.

takeown /f Web.config(Trick: If you receive any access denied error, make a copy and rename the original web.config file and change the copy to the original name)Now assign the ownership of the Web.config file to the administrators group.

Now open the config file and make sure to check the value multipleSiteBindingsEnabled=”true” Detailed steps available here.